channels.h

   1 /* $OpenBSD: channels.h,v 1.87 2006/07/21 12:43:36 dtucker Exp $ */
   2
   3 /*
   4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   6  *                    All rights reserved
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  */
  14 /*
  15  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #ifndef CHANNEL_H
  39 #define CHANNEL_H
  40
  41 #include "buffer.h"
  42
  43 /* Definitions for channel types. */
  44 #define SSH_CHANNEL_X11_LISTENER        1       /* Listening for inet X11 conn. */
  45 #define SSH_CHANNEL_PORT_LISTENER       2       /* Listening on a port. */
  46 #define SSH_CHANNEL_OPENING             3       /* waiting for confirmation */
  47 #define SSH_CHANNEL_OPEN                4       /* normal open two-way channel */
  48 #define SSH_CHANNEL_CLOSED              5       /* waiting for close confirmation */
  49 #define SSH_CHANNEL_AUTH_SOCKET         6       /* authentication socket */
  50 #define SSH_CHANNEL_X11_OPEN            7       /* reading first X11 packet */
  51 #define SSH_CHANNEL_INPUT_DRAINING      8       /* sending remaining data to conn */
  52 #define SSH_CHANNEL_OUTPUT_DRAINING     9       /* sending remaining data to app */
  53 #define SSH_CHANNEL_LARVAL              10      /* larval session */
  54 #define SSH_CHANNEL_RPORT_LISTENER      11      /* Listening to a R-style port  */
  55 #define SSH_CHANNEL_CONNECTING          12
  56 #define SSH_CHANNEL_DYNAMIC             13
  57 #define SSH_CHANNEL_ZOMBIE              14      /* Almost dead. */
  58 #define SSH_CHANNEL_MAX_TYPE            15
  59
  60 #define SSH_CHANNEL_PATH_LEN            256
  61
  62 struct Channel;
  63 typedef struct Channel Channel;
  64
  65 typedef void channel_callback_fn(int, void *);
  66 typedef int channel_infilter_fn(struct Channel *, char *, int);
  67 typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
  68
  69 struct Channel {
  70         int     type;           /* channel type/state */
  71         int     self;           /* my own channel identifier */
  72         int     remote_id;      /* channel identifier for remote peer */
  73         u_int   istate;         /* input from channel (state of receive half) */
  74         u_int   ostate;         /* output to channel  (state of transmit half) */
  75         int     flags;          /* close sent/rcvd */
  76         int     rfd;            /* read fd */
  77         int     wfd;            /* write fd */
  78         int     efd;            /* extended fd */
  79         int     sock;           /* sock fd */
  80         int     ctl_fd;         /* control fd (client sharing) */
  81         int     isatty;         /* rfd is a tty */
  82         int     wfd_isatty;     /* wfd is a tty */
  83         int     client_tty;     /* (client) TTY has been requested */
  84         int     force_drain;    /* force close on iEOF */
  85         int     delayed;                /* fdset hack */
  86         Buffer  input;          /* data read from socket, to be sent over
  87                                  * encrypted connection */
  88         Buffer  output;         /* data received over encrypted connection for
  89                                  * send on socket */
  90         Buffer  extended;
  91         char    path[SSH_CHANNEL_PATH_LEN];
  92                 /* path for unix domain sockets, or host name for forwards */
  93         int     listening_port; /* port being listened for forwards */
  94         int     host_port;      /* remote port to connect for forwards */
  95         char   *remote_name;    /* remote hostname */
  96
  97         u_int   remote_window;
  98         u_int   remote_maxpacket;
  99         u_int   local_window;
 100         u_int   local_window_max;
 101         u_int   local_consumed;
 102         u_int   local_maxpacket;
 103         int     extended_usage;
 104         int     single_connection;
 105
 106         char   *ctype;          /* type */
 107
 108         /* callback */
 109         channel_callback_fn     *confirm;
 110         void                    *confirm_ctx;
 111         channel_callback_fn     *detach_user;
 112         int                     detach_close;
 113
 114         /* filter */
 115         channel_infilter_fn     *input_filter;
 116         channel_outfilter_fn    *output_filter;
 117
 118         int     datagram;       /* keep boundaries */
 119 };
 120
 121 #define CHAN_EXTENDED_IGNORE            0
 122 #define CHAN_EXTENDED_READ              1
 123 #define CHAN_EXTENDED_WRITE             2
 124
 125 /* default window/packet sizes for tcp/x11-fwd-channel */
 126 #define CHAN_SES_PACKET_DEFAULT (32*1024)
 127 #define CHAN_SES_WINDOW_DEFAULT (4*CHAN_SES_PACKET_DEFAULT)
 128 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
 129 #define CHAN_TCP_WINDOW_DEFAULT (4*CHAN_TCP_PACKET_DEFAULT)
 130 #define CHAN_X11_PACKET_DEFAULT (16*1024)
 131 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
 132
 133 /* possible input states */
 134 #define CHAN_INPUT_OPEN                 0
 135 #define CHAN_INPUT_WAIT_DRAIN           1
 136 #define CHAN_INPUT_WAIT_OCLOSE          2
 137 #define CHAN_INPUT_CLOSED               3
 138
 139 /* possible output states */
 140 #define CHAN_OUTPUT_OPEN                0
 141 #define CHAN_OUTPUT_WAIT_DRAIN          1
 142 #define CHAN_OUTPUT_WAIT_IEOF           2
 143 #define CHAN_OUTPUT_CLOSED              3
 144
 145 #define CHAN_CLOSE_SENT                 0x01
 146 #define CHAN_CLOSE_RCVD                 0x02
 147 #define CHAN_EOF_SENT                   0x04
 148 #define CHAN_EOF_RCVD                   0x08
 149
 150 #define CHAN_RBUF       16*1024
 151
 152 /* check whether 'efd' is still in use */
 153 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 154         (compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
 155         (c->efd != -1 || \
 156         buffer_len(&c->extended) > 0))
 157 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 158         (compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
 159         c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
 160         buffer_len(&c->extended) > 0))
 161
 162 /* channel management */
 163
 164 Channel *channel_by_id(int);
 165 Channel *channel_lookup(int);
 166 Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
 167 void     channel_set_fds(int, int, int, int, int, int, u_int);
 168 void     channel_free(Channel *);
 169 void     channel_free_all(void);
 170 void     channel_stop_listening(void);
 171
 172 void     channel_send_open(int);
 173 void     channel_request_start(int, char *, int);
 174 void     channel_register_cleanup(int, channel_callback_fn *, int);
 175 void     channel_register_confirm(int, channel_callback_fn *, void *);
 176 void     channel_register_filter(int, channel_infilter_fn *, channel_outfilter_fn *);
 177 void     channel_cancel_cleanup(int);
 178 int      channel_close_fd(int *);
 179 void     channel_send_window_changes(void);
 180
 181 /* protocol handler */
 182
 183 void     channel_input_close(int, u_int32_t, void *);
 184 void     channel_input_close_confirmation(int, u_int32_t, void *);
 185 void     channel_input_data(int, u_int32_t, void *);
 186 void     channel_input_extended_data(int, u_int32_t, void *);
 187 void     channel_input_ieof(int, u_int32_t, void *);
 188 void     channel_input_oclose(int, u_int32_t, void *);
 189 void     channel_input_open_confirmation(int, u_int32_t, void *);
 190 void     channel_input_open_failure(int, u_int32_t, void *);
 191 void     channel_input_port_open(int, u_int32_t, void *);
 192 void     channel_input_window_adjust(int, u_int32_t, void *);
 193
 194 /* file descriptor handling (read/write) */
 195
 196 void     channel_prepare_select(fd_set **, fd_set **, int *, u_int*, int);
 197 void     channel_after_select(fd_set *, fd_set *);
 198 void     channel_output_poll(void);
 199
 200 int      channel_not_very_much_buffered_data(void);
 201 void     channel_close_all(void);
 202 int      channel_still_open(void);
 203 char    *channel_open_message(void);
 204 int      channel_find_open(void);
 205
 206 /* tcp forwarding */
 207 void     channel_set_af(int af);
 208 void     channel_permit_all_opens(void);
 209 void     channel_add_permitted_opens(char *, int);
 210 int      channel_add_adm_permitted_opens(char *, int);
 211 void     channel_clear_permitted_opens(void);
 212 void     channel_clear_adm_permitted_opens(void);
 213 int      channel_input_port_forward_request(int, int);
 214 int      channel_connect_to(const char *, u_short);
 215 int      channel_connect_by_listen_address(u_short);
 216 int      channel_request_remote_forwarding(const char *, u_short,
 217              const char *, u_short);
 218 int      channel_setup_local_fwd_listener(const char *, u_short,
 219              const char *, u_short, int);
 220 void     channel_request_rforward_cancel(const char *host, u_short port);
 221 int      channel_setup_remote_fwd_listener(const char *, u_short, int);
 222 int      channel_cancel_rport_listener(const char *, u_short);
 223
 224 /* x11 forwarding */
 225
 226 int      x11_connect_display(void);
 227 int      x11_create_display_inet(int, int, int, u_int *, int **);
 228 void     x11_input_open(int, u_int32_t, void *);
 229 void     x11_request_forwarding_with_spoofing(int, const char *, const char *,
 230             const char *);
 231 void     deny_input_open(int, u_int32_t, void *);
 232
 233 /* agent forwarding */
 234
 235 void     auth_request_forwarding(void);
 236
 237 /* channel close */
 238
 239 int      chan_is_dead(Channel *, int);
 240 void     chan_mark_dead(Channel *);
 241
 242 /* channel events */
 243
 244 void     chan_rcvd_oclose(Channel *);
 245 void     chan_read_failed(Channel *);
 246 void     chan_ibuf_empty(Channel *);
 247
 248 void     chan_rcvd_ieof(Channel *);
 249 void     chan_write_failed(Channel *);
 250 void     chan_obuf_empty(Channel *);
 251
 252 #endif